Additional Impacts Analysis

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Avenal Energy Project

Avenal Power Center, LLC

Introduction

As a part of the application for a Prevention of Significant Deterioration (PSD) permit

for the Avenal Energy Project (Project), Region 9 of the U.S. Environmental Protection

Agency (USEPA) has requested Avenal Power Center, LLC to submit a summary of the

additional impacts analysis conducted for the Project as required by federal regulation.

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The response below is divided into three parts, as follows: Class II visual impact

analysis, impacts on soils and vegetation, and growth-inducing impacts.

Class II Visual Impact Analysis

USEPA’s New Source Review Workshop Manual, Prevention of Significant Deterioration

and Nonattainment Area Permitting states the following:

Although each applicant for a PSD permit must perform an additional impacts

analysis, the depth of the analysis generally will depend on existing air quality,

the quantity of emissions, and the sensitivity of local soils, vegetation, and

visibility in the source's impact area.

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According to the above regulatory language, this summary additional impacts analysis

is sufficient because the Project has no visibility-related impact area as demonstrated in

Table 6.2-34 of the Application for Certification to the CEC (included in the transmittal

of the PSD application to USEPA on February 15, 2008), based on the following

analysis.

The Project’s maximum modeled ground-level concentrations of the three visibilityrelated criteria pollutants—nitrogen dioxide (NO2), sulfur dioxide (SO2), and particulate

matter with nominal aerodynamic diameter less than or equal to 10 microns (PM10)—

were compared with the following PSD significant impact levels:

• NO2 (annual average): 1 μg/m3

1 USEPA. New Source Review Workshop Manual, Prevention of Significant Deterioration and

Nonattainment Area Permitting (draft), Chapter D, October 1990.

2

Ibid.

3

Ibid, page D.1.
• SO2 (annual average): 1 μg/m3

• SO2 (24-hour average): 5 μg/m3

• SO2 (3-hour average): 25 μg/m3

• PM10 (annual average): 1 μg/m3

• PM10 (24-hour average): 5 μg/m3

None of the project’s maximum potential concentrations of NO2, SO2, and PM10 would

exceed the applicable PSD significant impact level; hence, no significant impact area

exists within which to analyze potential Class II area visibility impacts.

Although the Avenal Energy Project has no impact area, the Class II region that

surrounds the Project within 50 km4 was reviewed for potentially sensitive state or

federal parks, forests, monuments, or recreation areas. No such state or federal areas are

located in this rural part of the Central Valley.

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Impacts on Soils and Vegetation

Relative to potential impacts on soils and vegetation, the AFC included a discussion

of the Project’s maximum potential concentrations being below ambient air quality

standards, which are designed to protect public health and welfare, including effects on

animals, plants, soils and materials, as follows:

• Section 6.4 –Agriculture and Soils, pp. 6.4-8 = 6.4-9; and

• Section 6.6 – Biological Resources, p. 6.6-35.

EPA provided guidance

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in 1980 to determine if maximum modeled ground-level

concentrations of Project-emitted criteria pollutants NO2, SO2, and CO could have an

impact on plants, soils, and animals. As shown in Table 1, the maximum modeled

concentrations from the Project are well below (i.e., ranging between 0.02% and 34%)

the thresholds.

Table 1

Project Maximum Concentrations and EPA Guidance Levels

Criteria Pollutant

and Guidance

a

EPA Screening

Concentration

(μg/m3)

Modeled Maximum

Concentrations

b

(μg/m3)

Averaging

time

4

Ibid, page C.26, “The impact area is a circular area with a radius extending from the source to (1) the

most distant point where approved dispersion modeling predicts a significant ambient impact will occur, or

(2) a modeling receptor distance of 50 km, whichever is less.”

5 The nearest park is Colonel Allensworth State Historic Park, located 66 km east-southeast of the Project,

on Route 43 just south of its intersection with State Route J22 near Earlimart.

6 USEPA. A Screening Procedure for the Impacts of Air Pollution Sources on Plants, Soils, and Animals,”

EPA 450/2-81-078, December 1980.
Averaging Time

SO2 1-Hour 917 9.7 1 hour

SO2 3-Hour 786 4.3 3 hour

SO2 Annual 18 0.09 Annual

NO2 4-Hours 3,760 190 1 hour

NO2 1-Month 564 190 1 hour

NO2 Annual 94 0.5 Annual

CO Weekly 1,800,000 337 8 hour

a A Screening Procedure for the Impacts of Air Pollution Sources on Plants, Soils, and

Animals,” EPA 450/2-81-078, December 1980

b Table 6.2-31 on p. 6.2-66 of AFC Air Quality Section 6.2

Growth-Inducing Impacts

The less-than-significant potential growth inducing impacts on population, housing,

schools, utilities, and emergency and other services are discussed in the AFC, Section

6.10 – Socioeconomics, pages 6.10-19 through 6.10-32.